The present invention relates to a centrifugal pump assembly according to the preamble of the independent claim(s).
Centrifugal pump assemblies usually comprise an electrical drive motor and a centrifugal pump which is applied thereon and which may be designed in a single-stage or multi-stage manner. The impeller or impellers of the centrifugal pump are arranged on a shaft which is connected to the drive motor. In operation of the centrifugal pump assembly, an axial force acts on the shaft as a result of the reaction force of the delivered fluid, and this axial force must be accommodated by a thrust bearing. Thereby, there are several possibilities with regard the arrangement of such a thrust bearing. The thrust bearing may be arranged at the end of the shaft but also in the middle region of the shaft, which is advantageous with certain pumps.
With the arrangement in the middle region, there is the problem that alignment inaccuracies between the stationary and the moving bearing part of the thrust bearing may occur due to deflections or deformations of the shaft, which then lead to increased frictional losses and, as the case may be, an increased wear. In order to avoid this, a complicated alignment of the shaft and bearing parts is necessary, which however is not always possible in a perfect manner.
With regard to the above problem, it is an object of the present invention to provide a centrifugal pump assembly, with which a reliable functioning of the thrust bearing may be ensured even with a difficult position of installation.